Electric Priming /Back up Fuel Pump

[cal40john]

Originally Posted by IP Man

This was questioned and answered below in this thread but I think my pump is running all the time because I have an ignition switch and a start switch. The ignition switch is what starts the pump so I assume it is always running. Not aboard right now or I would check.

Now that I think about it it doesn't seem right running all the time. Any recommendations?

Thanks

IP Man

My Yanmar manual states that if the lift height is greater than ?? 1 meter?? you need to add an electric pump to the fuel system. My tank is in my keel, the lift height is more than the number in the manual, so the PO added an electric pump.

In troubleshooting for air leaks I have determined that either the electric or the mechanical pump will keep the engine running, but I have decided to follow specs and have both a mechanical and electric fuel pump running both at the same time.

I could someday remove the mechanical pump, but I like the idea that once it is running and don't need the starter anymore, my 3GM30 requires no electricity to run if I keep the mechanical pump. Theoretically not ideal since Yanmar must think that would be hard on the pump, but for an electrical emergency I'd be fine with that.

[IP Man]

Originally Posted by onestepcsy37

Most likely it has an engine driven mechanical fuel pump. There is a possibility that the the mechanical pump was removed and an electric pump installed to replace it. Better check it by following the fuel line from tank to injector pump.

I kept my mechanical pump (perkins 4-108) but decided to add an electric pump to make bleeding easier. Bleeding the 4-108 can be a PITA. The electric pump is on it's own on/off switch. I normally do not use it, but depend on the mechanical pump only.

My system looks like this;

fuel tank > electric pump > racor fuel filter > mechanical pump > engine fuel filter > injector pump.

Cool thanks for the detailed response

IP Man

[tpetrocci]

I have a similar question. What would be the basic steps to adding an electric fuel pump to my old but strong YSM 12?
Bypass the mechanical, or keep in the loop? The random air leak has defeated all efforts to locate.



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